Hi Michal,
It is up to you as to how often you check the top performers. One way is to just check them once a week. Another way would be to check the monthly and the weekly to see which robots show up for both the monthly and weekly time frames. This would tell you which robots have been best performers for a longer period of time. So there are various ways to use the FTMO app.
As for leverage, leverage is set by the broker or prop firm and not by the robot.
Alan,